The major objective of this research project is to develop methods which will reliably enable the nudibranch mollusc, Hermissenda crassicornis to be reared and maintained in laboratory culture for the purpose of establishing it as a standardized marine laboratory animal. These animals will be genetically and nutritionally defined as well as disease and pathogen free. They will be produced by precisely established methods of handling and tested by criteria designed to measure and predict their performance and reliability for research use. This will insure and support the use of Hermissenda as a research resource for investigating neural correlates of behavior and learning as well as its potential use as a new model system for studying biomineralization (i.e., initiation of calcification). Specific methods include (1) regulating adult diets to produce high fecundity rates and nutritionally rich ova which, in turn, promote high percentages of normal, synchronous development; (2) optimizing larval culture conditions to include nutrition, control of facultative pathogens and disease, and high percentages of metamorphic induction; (3) establishing morphologic criteria for defining and staging normal larval and juvenile development; and (4) begin establishing specific genetic strains of laboratory-reared animals for specific research purposes.